Variational mean-field approach to the double-exchange model

It has been recently shown that the double exchange Hamiltonian, with weak antiferromagnetic interactions, has a richer variety of first- and second-order transitions than previously anticipated, and that such transitions are consistent with the magnetic properties of manganites. Here we present a t...

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Detalles Bibliográficos
Autores: Alonso, J. L., Fernández Pérez, Luis Antonio, Guinea, F., Laliena, V., Martín Mayor, Víctor
Tipo de recurso: artículo
Fecha de publicación:2011
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/42572
Acceso en línea:https://hdl.handle.net/20.500.14352/42572
Access Level:acceso abierto
Palabra clave:53
Spectral moments method
Diluted ising-model
Phase-separation
Colossal magnetoresistance
Ferromagnetic manganites
Manganese perovskites
Critical exponents
Electronic models
Doped manganies
Spin dynamics.
Física (Física)
Física-Modelos matemáticos
22 Física
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oai_identifier_str oai:docta.ucm.es:20.500.14352/42572
network_acronym_str ES
network_name_str España
repository_id_str
spelling Variational mean-field approach to the double-exchange modelAlonso, J. L.Fernández Pérez, Luis AntonioGuinea, F.Laliena, V.Martín Mayor, Víctor53Spectral moments methodDiluted ising-modelPhase-separationColossal magnetoresistanceFerromagnetic manganitesManganese perovskitesCritical exponentsElectronic modelsDoped manganiesSpin dynamics.Física (Física)Física-Modelos matemáticos22 FísicaIt has been recently shown that the double exchange Hamiltonian, with weak antiferromagnetic interactions, has a richer variety of first- and second-order transitions than previously anticipated, and that such transitions are consistent with the magnetic properties of manganites. Here we present a thorough discussion of the variational mean-field approach that leads to these results. We also show that the effect of the Berry phase turns out to be crucial to produce first-order paramagnetic-ferromagnetic transitions near half filling with transition temperatures compatible with the experimental situation. The computation relies on two crucial facts: the use of a mean-field ansatz that retains the complexity of a system of electrons with off-diagonal disorder, not fully taken into account by the mean-field techniques, and the small but significant antiferromagnetic superexchange interaction between the localized spins.American Physical SocietyUniversidad Complutense de Madrid20112011-02-0120112011-02-01journal articlehttp://purl.org/coar/resource_type/c_6501info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/20.500.14352/42572reponame:Docta Complutenseinstname:Universidad Complutense de Madrid (UCM)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:docta.ucm.es:20.500.14352/425722026-06-02T12:44:21Z
dc.title.none.fl_str_mv Variational mean-field approach to the double-exchange model
title Variational mean-field approach to the double-exchange model
spellingShingle Variational mean-field approach to the double-exchange model
Alonso, J. L.
53
Spectral moments method
Diluted ising-model
Phase-separation
Colossal magnetoresistance
Ferromagnetic manganites
Manganese perovskites
Critical exponents
Electronic models
Doped manganies
Spin dynamics.
Física (Física)
Física-Modelos matemáticos
22 Física
title_short Variational mean-field approach to the double-exchange model
title_full Variational mean-field approach to the double-exchange model
title_fullStr Variational mean-field approach to the double-exchange model
title_full_unstemmed Variational mean-field approach to the double-exchange model
title_sort Variational mean-field approach to the double-exchange model
dc.creator.none.fl_str_mv Alonso, J. L.
Fernández Pérez, Luis Antonio
Guinea, F.
Laliena, V.
Martín Mayor, Víctor
author Alonso, J. L.
author_facet Alonso, J. L.
Fernández Pérez, Luis Antonio
Guinea, F.
Laliena, V.
Martín Mayor, Víctor
author_role author
author2 Fernández Pérez, Luis Antonio
Guinea, F.
Laliena, V.
Martín Mayor, Víctor
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Universidad Complutense de Madrid
dc.subject.none.fl_str_mv 53
Spectral moments method
Diluted ising-model
Phase-separation
Colossal magnetoresistance
Ferromagnetic manganites
Manganese perovskites
Critical exponents
Electronic models
Doped manganies
Spin dynamics.
Física (Física)
Física-Modelos matemáticos
22 Física
topic 53
Spectral moments method
Diluted ising-model
Phase-separation
Colossal magnetoresistance
Ferromagnetic manganites
Manganese perovskites
Critical exponents
Electronic models
Doped manganies
Spin dynamics.
Física (Física)
Física-Modelos matemáticos
22 Física
description It has been recently shown that the double exchange Hamiltonian, with weak antiferromagnetic interactions, has a richer variety of first- and second-order transitions than previously anticipated, and that such transitions are consistent with the magnetic properties of manganites. Here we present a thorough discussion of the variational mean-field approach that leads to these results. We also show that the effect of the Berry phase turns out to be crucial to produce first-order paramagnetic-ferromagnetic transitions near half filling with transition temperatures compatible with the experimental situation. The computation relies on two crucial facts: the use of a mean-field ansatz that retains the complexity of a system of electrons with off-diagonal disorder, not fully taken into account by the mean-field techniques, and the small but significant antiferromagnetic superexchange interaction between the localized spins.
publishDate 2011
dc.date.none.fl_str_mv 2011
2011-02-01
2011
2011-02-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/20.500.14352/42572
url https://hdl.handle.net/20.500.14352/42572
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv American Physical Society
publisher.none.fl_str_mv American Physical Society
dc.source.none.fl_str_mv reponame:Docta Complutense
instname:Universidad Complutense de Madrid (UCM)
instname_str Universidad Complutense de Madrid (UCM)
reponame_str Docta Complutense
collection Docta Complutense
repository.name.fl_str_mv
repository.mail.fl_str_mv
_version_ 1869406533608013824
score 15.301629

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